1. Field of the Invention
The present invention relates to a Front Opening Unified Pod (FOUP), which is a next-generation wafer carrier for holding, transporting, and storing a substrate such as a semiconductor wafer. The present invention further relates to a load port for opening and closing the pod, to a load port system including the FOUP, and to a method of treating or producing a substrate using the load port system. More particularly, the present invention is intended to improve the reliability of opening/closing action of a door of a FOUP and prevent entry of particles (extraneous particles) into a substrate treatment unit with sufficient reliability.
2. Background Art
In contrast with open cassettes which have conventionally been used (e.g., open cassettes which are incompatible with 8-inch wafers and typified by SEMI Standard E1.9), a side-door integral-type wafer carrier holds wafers in an enclosed space, to thereby protect wafers from dust particles in the atmosphere or from chemical contamination.
FIG. 9 is a perspective view for describing a FOUP system which is a side-door integral-type wafer carrier and has conventionally been used for manufacturing semiconductor devices. As shown in FIG. 9, P30 denotes a FOUP system; P1 denotes a FOUP shell (e.g., a pod main unit); P2 denotes a FOUP door; P5 denotes a latch key hole; P8 denotes a sealing substance (e.g., a packing); P9 denotes a door clamping mechanism (e.g., a stopper mechanism); and P10 denotes a retainer.
The FOUP system P30 shown in FIG. 9 belongs to Front Opening Unified Pod systems, which are next-generation wafer carriers for holding, transporting, and storing substrates for use as photo-reticles, substrates for display panels such as substrates for liquid-crystal display panels or plasma displays, hard disk substrates, and substrates such as wafers for use in fabricating electronic devices such as semiconductor devices. The FOUP system P30 is one described in, for example, a catalog describing F300 Wafer Carriers manufactured by Entegris. Information about detailed dimensions of the FOUP system are described in SEMI Standards E57, E1.9, E47.1. Such a side-door integral-type wafer carrier is hereinafter generically called a xe2x80x9cFOUP system.xe2x80x9d
In contrast with open cassettes which have conventionally been used (e.g., open cassettes which are incompatible with 8-inch wafers and typified by SEMI Standard E1.9), the conventional FOUP system holds wafers in an enclosed space, to thereby protect the wafers from dust particles in the atmosphere or from chemical contamination. In order to maintain air-tightness, the sealing substance P8 (packing) is provided along the edge of the FOUP door P2. The FOUP door P2 has a wafer press mechanism called the retainer P10, beams called a wafer teeth section (not shown) for seating wafers, and a mechanical opening/closing mechanism such as the door clamp mechanism P9.
In order to open and close such a FOUP system P30 in a semiconductor manufacturing system (e.g., a substrate treatment unit), there is a necessity for use of a load port having a FIMS (Front-Opening Interface Mechanical Standard) surface specified by a SEMI standard.
The load port has a kinematic pin for sustaining the FOUP system P30 in a fixed position, a FIMS door which engages with the FOUP door P2 and is taken into an mini-environment defined in the FOUP system 30 along with the FOUP door P2 after the FOUP door P2 has been opened (i.e., after a latch key has been rotated), and a housing surface for isolating the mini-environment from the outside. An area in the housing surface of the load port which is to engage with a FOUP sealing surface of the FOUP system P30 is called an FIMS sealing surface.
A wafer holding section of such a conventional wafer carrier (or FOUP system) P30 is primarily made up of the FOUP shell section P1 and the FOUP door P2 which is an open/close door. In order to secure the FOUP door P2 to the FOUP shell section P1, there is a necessity for the door clamping mechanism P9 (e.g., a stopper mechanism). For this reason, the wafer holding section has a complicated structure, and a hole must be provided in the FOUP door P2. Further, a hole to be clamped for securing a door must be provided even in the FOUP shell section P1. Further, the FOUP shell section P1 must have a thick section and a sealing section.
At worksites, a plurality of types of load ports and a plurality of types of wafer carrier jigs (FOUP systems) P30 must be used in combination. Accordingly, higher dimensional accuracy is required. Even minute deformation greatly affects the reliability of opening and closing action of a FOUP door.
The background art encounters the following problems. A first drawback of the background art is that, when the sealing substance P8 (i.e., a packing) provided on the sealing surface of the FOUP shell section P1 is brought into contact with the FIMS sealing surface, sustaining the FOUP system P30 in such a position and opening/closing the FOUP system P30 with high reliability are difficult.
A second problem is that, when the sealing surface of the FOUP shell section P1 remains in contact with the FIMS sealing surface, flow of clean air from the mini-environment defined in the treatment unit (i.e., the inside of the FOUP system P30) to the outside thereof is limited. This is not preferable in terms of contamination. Particularly, prevention of entry of particles (extraneous particles) into the treatment unit (the inside of the FOUP system P30) is insufficiently reliable.
The present invention has been conceived to solve these drawbacks of the background art and is aimed at providing a load port structure and a FOUP structure which enable high-yield production of integrated circuits by means of improving the reliability of opening/closing action of a FOUP door and preventing entry of particles into the treatment unit with sufficient reliability. Further, the present invention has been conceived to provide a production method using the improved load port structure and the FOUP structure.
According to the aspects of the present invention, a load port system for use with a substrate treatment unit is improved, in which a wafer carrier having wafers stored therein is placed on a load port of the substrate treatment unit, a load port door opposes a door of the wafer carrier, and a sealing surface provided around the load port door opposes a sealing surface provided around a door opening section of the wafer carrier.
In the load port system, a plurality of protuberances, which are to be brought into contact with the sealing surface provided around the door opening section of the wafer carrier, are provided on the sealing surface formed around the load port door of the substrate treatment unit.
Alternatively, a plurality of protuberances, which are to be brought into contact with the sealing surface provided around the load port door of the substrate treatment unit, are provided on the sealing surface formed around the door opening section of the wafer carrier.
Thereby, a predetermined clearance is maintained between the sealing surface provided around the load port door and the sealing surface provided around the door opening section of the wafer carrier.
Other features and advantages of the invention will be apparent from the following description taken in connection with the accompanying drawings.